The present invention relates to a brushless motor such as a motor for a blower unit of an air conditioning system of automotive vehicles.
Japanese Patent Provisional Publication No. 2000-32729 discloses a brushless motor employed as a motor for a blower fan of an automotive air conditioner unit. Particularly, this disclosed brushless motor is arranged such that switching devices for switching directions of drive current supplied to exciting coils of a stator are fitted with a heat sink by means of elastic clips and are connected with an electric circuit board by means of soldering.
However, such a brushless motor has been required to be further improved in productivity.
It is therefore an object of the present invention to provide an improved brushless motor which performs high productivity and high reliability.
An aspect of the present invention resides in a brushless motor which comprises a stator, a rotor, an electric circuit board, a heat sink, a plurality of switching devices and a pressing member. The stator comprises a plurality of exciting coils, and the rotor is rotatable relative to the stator. The electric circuit board comprises a control circuit for controlling rotation of the rotor and through-holes. The heat sink comprises a heat radiating portion and a pair of supporting legs extending from opposite end portions of the heat radiating portion. The heat sink is disposed on the electric circuit board by contacting an end portion of each of the supporting legs with the electric circuit board. The switching devices are electrically connected with the electric circuit board and controls the direction of drive current supplied to exciting coils of a stator. The pressing member comprises a pressing portion, a pair of positioning portions extending from opposite end portions of the pressing portion, and a pair of connecting portions projecting from the pair of positioning portions respectively. The pressing portion presses the switching devices to the heat sink by engaging the connecting portions with the heat sink. The positioning portions are inserted into the through-holes of the electric circuit board respectively.
Another aspect of the present invention resides in an assembly structure of a brushless motor. The assembly structure comprises a circuit board, a heat sink, a plurality of switching devices and a pressing member. The circuit board comprises a control circuit for controlling a rotation of a rotor relative to a stator of the brushless motor. The heat sink comprises a heat radiating portion and a pair of supporting legs extending from both opposite sides of the heat radiating portion. A free end portion of each supporting leg is in contact with the electric circuit board. The switching devices are electrically connected with the electric circuit board and controls a direction of drive current supplied to exciting coils of the stator. The pressing member comprises a pressing portion, a pair of positioning portions perpendicularly extending from opposite end portions of the pressing portion, and a pair of connecting portions projecting from the pair of positioning portions respectively. The connecting portions are engaged with the supporting legs respectively. The pressing portion presses the switching devices to the heat sink. The positioning portions are inserted into the through-holes of the electric circuit board respectively.
The other objects and features of this invention will become understood from the following description with reference to the accompanying drawings.